Running the Simple Frequency Generator example produces the output waveform shown above. Running the Sine Output example produces a variable frequency output with a similar wave shape. The time scale for the image is 0.2 ms per division. About 2 weeks ago when I used an oscilloscope to look at the waveform produced by the Sine Output example the output was a variable frequency Sine Wave.

Here is the Self Test Output.

xecuting test suite...

usb_id = 583430353230157811

Read USB ID... OK

input_offset = 19

Test zero offset... OK

output_offset_neg = -1219

output_offset_pos = 1250

Test offset adjustment... FAILoutput_offset_pos: 1250 is not between 748 and 1148

input_amp_6 = 3074

Test amplitude adjustment... FAILinput_amp_6: 3074 is not between 3200 and 3400

input_freq_1k = 1000

input_phase_1k = 29

Test frequency and phase... FAILinput_phase_1k: 29 is not between 999 and 1001Send a character to rerun test suite.

Are there any adjustments I can make to get Tsunami to produce a sinusoidal output.

hrh1818

nickjohnson
—
2015-09-21T06:19:10Z —
#2

Hi Howard,

What are you using to measure the output waveform? Is there anything connected to the output besides the measurement device?

What happens if you decrease the output amplitude to, say, 0.5Vpp?

-Nick

hrh1818
—
2015-09-21T23:29:34Z —
#3

The wave form picture was taken with: 1. A BNC Tee connector connected to Tsunami's output connector. 2. One of the Tee's output's is directly connected to Tsunami;s input. 3. The Tee's other output was connected to a 2,000 ohm load. 4. A USB oscilloscope was used to monitor the signal applied to the 2,000 ohm load. 5. I am used the same USB oscilloscope I used when I saw sinusoidal outputs 2 weeks ago.6. The USB oscilloscope uses a 5 volt wall wort. There is no ground loop.

Today I removed the 2,000 ohm load and made some additional tests.1. A BNC Tee connector is connected to Tsunami's output connector. 2. One of the Tee's output's is directly connected to Tsunami's input. 3. The Tee's other output is connected to the input of a USB oscilloscopeObservations1. For the Simple Frequency Generator and Sine output examples the output wave forms were exactly alike the wave form shown in my first post. 2. Removing the cable going from Tsunami's output to Tsunami's input did not change the wave shape. 3. How do you set the output amplitude of the Simple Frequency Generator and Sine output examples? There is no line of code in the examples for setting the amplitude.

When using a modified version of your Component Network code I see.1. A 20 millivolt peak to peak high frequency noise signal. Setting the amplitude to values between 0,5 and 4 volts does not change Tsunami's 20 millvolts peak to peak output signal.2. When the set amplitude code is commented out Tsunami's output wave form is exactly like the wave form in the picture I posted.

Side issue Arduino couldn't find a definition for this function Tsunami.enablePhaseMeasurement(); in the Tsunami library.

Thanks for the details. To set amplitude, use the regular Frequency Generator sketch and issue the command 'amp 0.5'.

blinkenlight
—
2015-09-22T18:17:35Z —
#5

There are a few more simple things you could try; such as disconnecting the USB scope and the Tsunami, and measuring something like an AA battery (or two) with the scope, both directions, just to make sure its input isn't somehow fried; measuring the output voltage of the Tsunami with a simple digital multimeter directly at the BNC out with nothing else connected, to confirm the RMS is indeed under 1V; measuring the supply voltage of the Tsunami (eg. at the unpopulated pin header) with the USB scope to make sure it's a stable 5V and there are no shenanigans of any sort going on; you could of course also try to trace the generated signal along different points on the Tsunami but without a schematic to look at I can't really tell you where exactly to look. I'm also assuming of course you're not using a 10:1 probe that the USB scope doesn't know about or something, and the 2K resistor is really a 2K resistor not a 2R one or a diode or somesuch...

hrh1818
—
2015-09-22T21:18:38Z —
#6

Hello Nick,

Problem solved.

Part of the problem was caused by the inconsistency in documentation. The Measuring Component Networks and Measuring Frequency Response examples imply the amplitude units are volts. Whereas the Reference Document says amplitude units are millivolts. By setting the amplitude in millivolts I got the expected results, Previously when I used volts for the units Tsunami's output signal was to small to be seen.

The other part of the problem is caused by Tsunami clipping the output signal. As of today the maximum amplitude I can specify is 2100 millivolts. Larger amplitudes cause clipping. Whereas when I first monitored by the output signal the Sine Output example would work with 3000 millivolt amplitudes.

hrh1818

hrh1818
—
2015-09-22T21:28:16Z —
#7

Hello blinkenlight,

Thank you for your comments. I will try to remember them the next time I do some trouble shooting.